Study Overview: This study tests if a medicine called TEV-56286 can help treat Multiple System Atrophy (MSA), a rare disorder affecting the nervous system. The main goal is to see if the medicine works, and also to check its safety. Study Details: Participants will be in the study for 56 weeks. This includes a screening period (up to 4 weeks), a 48-week treatment phase where neither the doctors nor the participants know who is getting the real medicine or a placebo (a pill with no medicine), and a follow-up visit 4 weeks after. The whole study will last about 27 months. Eligibility: Participants must have MSA and be stable in terms of health. Women who can have children must test negative for pregnancy and use effective birth control. Men must also use effective birth control with partners. People cannot join if they have a history of substance abuse, are pregnant, or have certain allergies.

• Study lasts 56 weeks per participant.
• Participants will not know if they receive the real medicine or placebo.
• Participants must follow specific health and safety requirements.